This invention relates generally to an apparatus for use in an engine starting system and more specifically to an engine starting apparatus having a ball drive arrangement for transmitting forces between a drive member and a pinion gear which engages an engine ring gear.
There are many known devices for use in engine starting systems to transmit forces to effect a starting of the engine. Some of these known starting devices are disclosed in U.S. Pat. Nos. 3,593,697; 3,304,790; 1,208,115; and 1,178,788.
Although these known starting devices have been more or less satisfactory in their mode of operation, at least some of them have relied upon pinion gear movement on a helix to achieve rotational and axial movement of the pinion gear relative to a drive shaft when the pinion gear teeth are in a misaligned relationship with the teeth on an engine gear. These systems require a relatively high initial actuating force. After a period of service, abutments become worn and are ineffective to move the pinion gear in the desired manner. This wear is due to deterioration of lubricants, and the picking up of metal, soil or other foreign particles on sliding surfaces. In addition, with certain known starting systems severe damage can occur to the starter drive arrangement when the starting motor remains energized after the engine is started. Finally, it is extremely difficult, if not impossible, to hold relatively small pinion pitch diameter tolerances due to an accumulation of shaft, inner sleeve, outer sleeve and gear cutting tolerances or shaft, sleeve, outer helix, inner helix and spur gear cutting tolerances with certain known engine starting systems.